src: keep main-thread Isolate attached to platform during Dispose

This works around a situation in which the V8 WASM code calls into the platform while the Isolate is being disposed. This goes against the V8 API constract for `v8::Platform`. In lieu of a proper fix, it should be okay to keep the Isolate registered; the race condition fixed by 25447d8 cannot occur for the `NodeMainInstance`’s Isolate, as it is the last one to exit in any given Node.js process. This partially reverts 25447d8. Refs: nodejs#30909 Refs: nodejs#31752 PR-URL: nodejs#31795 Reviewed-By: Denys Otrishko <[email protected]> Reviewed-By: James M Snell <[email protected]>
targos · Feb 14, 2020 · e460f8c · e460f8c
1 parent 75311db
commit e460f8c
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/src/node_main_instance.cc b/src/node_main_instance.cc
@@ -102,8 +102,12 @@ NodeMainInstance::~NodeMainInstance() {
   if (!owns_isolate_) {
     return;
   }
-  platform_->UnregisterIsolate(isolate_);
+  // TODO(addaleax): Reverse the order of these calls. The fact that we first
+  // dispose the Isolate is a temporary workaround for
+  // https://github.com/nodejs/node/issues/31752 -- V8 should not be posting
+  // platform tasks during Dispose(), but it does in some WASM edge cases.
   isolate_->Dispose();
+  platform_->UnregisterIsolate(isolate_);
 }
 
 int NodeMainInstance::Run() {